【剑指offer】题61：二叉树序列化、反序列化

使用stringstream

http://blog.csdn.net/xw20084898/article/details/21939811

stringstream 是 C++ 提供的另一个字串型的串流(stream)物件，和之前学过的 iostream、fstream 有类似的操作方式。要使用 stringstream， 必須先加入這一行：

#include <sstream>

stringstream 主要是用在將一個字串分割，可以先用 clear( )以及 str( ) 將指定字串設定成一开始的內容，再用 >> 把个別的资料输出，例如：

string s;
stringstream ss;
int a；
char b;
string c;
getline(cin, s);
ss.clear();
ss.str(s);
ss >> a >> b >> c;

#include <iostream>
#include <string>
#include <sstream>
using namespace std;

struct TreeNode {
int val;
struct TreeNode *left;
struct TreeNode *right;
TreeNode(int x) :
val(x), left(NULL), right(NULL) {}
};

string Serialize(TreeNode *root)
{
string str;
if (root == NULL)
{
str = "$,";
return str;
}
stringstream stream;
stream << root->val<<",";

stream << Serialize(root->left);
stream << Serialize(root->right);
str = stream.str();
return str;

}
TreeNode* Deserialize(stringstream& stream)
{
TreeNode* pRoot(NULL);
char c;
stream >> c;
if<
4000
/span> (c == '$')
{
stream >> c;
return pRoot;
}
int num(0);
while (c != ',')
{
num = num * 10 + c - '0';
stream >> c;
}
pRoot = new TreeNode(num);
pRoot->left = Deserialize(stream);
pRoot->right= Deserialize(stream);
return pRoot;
}

TreeNode* Deserialize(string str)
{
TreeNode * pRoot(NULL);
if (str.empty())
{
return pRoot;
}
stringstream stream(str);
return Deserialize(stream);
}

int main()
{
string str = "100,50,$,$,150,$,$";
TreeNode* root;
root = Deserialize(str);

auto tmp = Serialize(root);
root = Deserialize(str);

tmp = Serialize(root);
return 0;
}